plants Article OsbHLH073 Negatively Regulates Internode Elongation and Plant Height by Modulating GA Homeostasis in Rice 1, 2, 3 4 2 Jinwon Lee y, Sunok Moon y, Seonghoe Jang , Sichul Lee , Gynheung An , Ki-Hong Jung 2,* and Soon Ki Park 1,* 1 School of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea;
[email protected] 2 Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 17104, Korea;
[email protected] (S.M.);
[email protected] (G.A.) 3 World Vegetable Center Korea Office (W.K.O), Jellabuk-do 55365, Korea;
[email protected] 4 Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu 42988, Korea;
[email protected] * Correspondence:
[email protected] (K.-H.J.);
[email protected] (S.K.P.) These authors contributed equally to this work: J.L., S.M. y Received: 5 March 2020; Accepted: 21 April 2020; Published: 23 April 2020 Abstract: Internode elongation is one of the key agronomic traits determining a plant’s height and biomass. However, our understanding of the molecular mechanisms controlling internode elongation is still limited in crop plant species. Here, we report the functional identification of an atypical basic helix-loop-helix transcription factor (OsbHLH073) through gain-of-function studies using overexpression (OsbHLH073-OX) and activation tagging (osbhlh073-D) lines of rice. The expression of OsbHLH073 was significantly increased in the osbhlh073-D line. The phenotype of osbhlh073-D showed semi-dwarfism due to deficient elongation of the first internode and poor panicle exsertion. Transgenic lines overexpressing OsbHLH073 confirmed the phenotype of the osbhlh073-D line.